Helmholtz muffler for vehicle

ABSTRACT

A Helmholtz muffler for a vehicle may include a muffler housing having an internal space divided into a plurality of expansion chamber; a resonance chamber formed hermetically in a vehicle body member; and a connection tube configured to be connected to one of the expansion chambers of the muffler housing and to the resonance chamber.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2018-0080480 filed on Jul. 11, 2018, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a Helmholtz muffler for a vehicle, and more particularly, to a Helmholtz muffler for a vehicle having a novel configuration in which a vehicle body member supporting a vehicle body is employed as a resonance chamber.

Description of Related Art

Generally, an exhaust system for a vehicle includes an exhaust manifold of an engine, an exhaust pipe connected to the exhaust manifold and extending toward a rear side of the vehicle body, a catalytic converter mounted at a predetermined position of the exhaust pipe to purify exhaust gas, and a muffler mounted to an end portion of the exhaust pipe to attenuate exhaust noise.

FIG. 1 is a cross-sectional view showing a conventional Helmholtz muffler for a vehicle.

The muffler includes a case 10 having a predetermined volume, at least three or more baffles 15, 16, 17 disposed in an internal space of the muffler housing 10 in a longitudinal direction and spaced from each other to divide the internal space of the muffler housing 10 into a plurality of expansion chambers 11, 12, 13 and one resonance chamber 14, an internal tube 18 passing through and coupled to each of the baffles 15, 16 and 17 and disposed in the muffler housing 10 in the longitudinal direction thereof, a connection tube 19 connected between the baffles 15 and 16, and at least two or more external tubes 20 passing through and coupled to each of the baffles 15, 16 and 17 and disposed in the muffler housing 10 in the longitudinal direction thereof.

At the instant time, an exhaust pipe 22 is connected to an inlet end portion of the internal tube 18, and an outlet end portion of the internal tube 18 is disposed in the sealed resonance chamber 14.

Furthermore, an inlet end portion of the external tube 20 is disposed in the first expansion chamber 11, and an outlet end portion of the external tube 20 which is a portion though which exhaust gas is lastly discharged is disposed in a state of passing though the resonance chamber 14 and being then exposed to the outside.

As may be seen from FIG. 2A, the first baffle 15 and the second baffle 16 of the baffles 15, 16, 17 have a plurality of perforations 21 formed therein, and the third baffle 17 is configured not to have a perforation as may be seen in FIG. 2B.

Therefore, the first expansion chamber 11 and the second expansion chamber 12 are in communication with each other by the perforations 21 of the first baffle 15, the second expansion chamber 12 and the third expansion chamber 13 are in communication with each other by the perforations 21 of the second baffle 16, and the third expansion chamber 13 and the first expansion chamber 11 are in communication with each other by the perforations 21 of the first and second baffles 15 and 16 and are simultaneously in communication with each other by the connection tube 19.

On the other hand, since the third baffle 17 has a closed configuration in which no perforation is formed, the resonance chamber 14 is formed as a sealed space and accommodates exhaust gas discharged from the outlet end portion of the internal tube 18 to function as a Helmholtz resonator which reduces noise within the low-frequency range.

Meanwhile, a plurality of perforations 18-1 are formed in a section, which passes between the second baffle 16 and the third baffle 17, in the entire length region of the internal tube 18.

Therefore, when exhaust gas is discharged from the exhaust pipe 22 to the internal tube 18, exhaust gas is discharged continuously through a process in which exhaust gas flows into and is discharged to the third expansion chamber 13 via the perforations 18-1 of the internal tube 18, a process in which exhaust gas is discharged from the third expansion chamber 13 to the second expansion chamber 12 via the perforations 21 of the second baffle 16, a process in which exhaust gas is discharged from the second expansion chamber 12 to the first expansion chamber 11 via the perforations 21 of the first baffle 15 and is simultaneously discharged from the third expansion chamber 13 to the first expansion chamber 11 via the connection tube 18, and a process in which exhaust gas passes through the external tube 20 from the first expansion chamber 11 and is then discharged to the outside.

As described above, while exhaust gas flowing into the internal tube 18 passes sequentially through the third expansion chamber 13, the second expansion chamber 12 and the first expansion chamber 11, exhaust noise (exhaust noise excluding low-frequency component in the entire RPM region of an engine) is reduced.

Exhaust gas flowing into the internal tube 18 is also discharged to the resonance chamber 14 through the outlet end portion of the internal tube 18 and is trapped. In the resonance chamber 14, noise of the low-frequency component in exhaust noise, which is unpleasant to an ear of human, is reduced.

However, the above described conventional muffler has the following problems.

Firstly, the Helmholtz resonance chamber formed together with several expansion chambers dividing an internal space of the muffler into several sections aims at reducing noise at a specific frequency (noise within the low frequency range). However, it is difficult to change factors (Helmholtz resonance frequency, etc.) determining the resonance frequency, so that there is a limitation in reducing low-frequency noise which is a target reduction region.

Secondly, when a capacity (volume) of the resonance chamber in the muffler is increased, an effect of reduction of noise within the low frequency range may be enhanced. However, as the resonance chamber capacity is increased, a size of the muffler housing of the muffler becomes larger, so that complicated processes such as a change of layout design of an exhaust system may be followed. Furthermore, when the capacity of the resonance chamber is increased without increasing the size of the muffler housing of the muffler, the capacity of the expansion chamber is reduced in reverse proportion to the capacity of the resonance chamber, and therefore, there is a problem that an effect of reduction of noise within the entire RPM zone obtained by the expansion chamber is inevitably reduced.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and may not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a Helmholtz muffler for a vehicle having a novel configuration in which an internal space of a case of the muffler is divided into several sections used as expansion chambers and a hollow vehicle body member is connected to and in communicated with the muffler housing of the muffler to be used as a resonance chamber, so that both a capacity (volume) of the resonance chamber and a capacity of the expansion chambers may be increased, enhancing an effect of reduction of noise within the entire RPM region obtained by the expansion chambers as well an effect of reduction of noise within the low frequency region obtained by the resonance chamber.

In various aspects of the present invention, various aspects of the present invention provide a Helmholtz muffler for a vehicle including a muffler housing having an internal space divided into a plurality of expansion chamber; a resonance chamber formed hermetically in a vehicle body member; and a connection tube configured to be connected to one of the expansion chambers of the muffler housing and to the resonance chamber.

Partitions by which a capacity of the resonance chamber is determined may be disposed at both sides of the resonance chamber, respectively. Here, the partitions may be integrally welded to a vehicle body member.

The connection tube may be connected to and be in communication with the expansion chamber to which exhaust gas is finally discharged, among the plurality of expansion chambers.

A bellows pipe which may be moved vertically and horizontally may be adopted as the connection pipe to absorb a displacement of behavior of the muffler housing, and an upper end portion and a lower end portion of the bellows pipe may be welded to the vehicle body member and the muffler housing, respectively.

Furthermore, a first baffle and a second baffle may be mounted in the muffler housing in a longitudinal direction and spaced from each other to form a space between one side wall of the muffler housing and the first baffle as a first expansion chamber, to form a space between the first baffle and the second baffle as a second expansion chamber, and to form a space between the other side wall of the muffler housing and the second baffle as a third expansion chamber.

Furthermore, an internal tube passing through the first baffle and the second baffle may be disposed in the muffler housing, and an exhaust pipe is connected to an inlet end portion of the internal tube and an outlet end portion of the internal tube is disposed in the third expansion chamber.

Also, an external tube passing through the first baffle and the second baffle may be disposed in the muffler housing. Here, an inlet end portion of the external tube may be disposed in the first expansion chamber and an outlet end portion may be disposed to pass through the other side wall of the muffler housing and to be exposed to the outside.

Furthermore, a connection tube configured to allow the first expansion chamber and the third expansion chamber to be in communication with each other may be connected between the first baffle and the second baffle.

Furthermore, a plurality of perforations may be formed in a section, which is disposed in the third expansion chamber, of the entire length region of the internal tube.

Other aspects and exemplary embodiments of the disclosure are discussed infra.

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger vehicles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. The above and other features of the disclosure are discussed infra.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a conventional Helmholtz muffler for a vehicle;

FIG. 2A and FIG. 2B are front views illustrating a configuration of a baffle defining expansion chambers in the muffler;

FIG. 3 is a perspective view exemplarily illustrating a Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention;

FIG. 4 is a cross-sectional view exemplarily illustrating the Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention;

FIG. 5 is a cross-sectional view exemplarily illustrating a flow of exhaust gas in the Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention;

FIG. 6 is a cross-sectional view for comparing a state before a reduction of case capacity of the Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention with a state after a reduction of case capacity; and

FIG. 7 is a view showing another exemplary embodiment for a configuration for connecting a bellow pipe of the Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention.

It may be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as included herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particularly intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the other hand, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the present invention. Furthermore, since the present invention may be implemented in various forms, the present invention is not limited to the exemplary embodiments described herein.

In the whole description, it will be understood that when a component is referred to as being “comprising” any component, it does not exclude other components, but can further comprises the other components unless otherwise specified.

To clearly describe the present invention, parts which are not related to the description are omitted, and the same reference numerals are used for indicating the same or similar components throughout the drawings and detail description.

FIG. 3 and FIG. 4 are views illustrating a Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention, and the reference numeral “300” indicates a vehicle body member supporting a vehicle body.

The vehicle body member 300 is a side member disposed in a longitudinal direction of a vehicle body or a cross member disposed in a widthwise direction of the vehicle body, and is provided in the shape of a hollow square cross-section beam.

The main feature of the present invention is that the vehicle body member 300 may be configured to be used as a resonance chamber of the muffler.

In other words, although the conventional muffler is constructed to have a configuration in which an internal space of a case is divided into three expansion chambers and one resonance chamber by three baffles, the muffler of the present invention is characterized in that an internal space of a case 100 is divided into only three expansion chambers by two baffles and an internal space of the vehicle body member 300 may be used as a resonance chamber.

To the present end, the muffler of the present invention includes the muffler housing 100 configured to allow the internal space thereof to be divided into three expansion chambers by two baffles, a resonance chamber 310 hermetically formed in the vehicle body member 300, a connection pipe 200 connected between one of three divided expansion chambers in the muffler housing 100 and the resonance chamber 310, and the like.

Since the entire internal space of the vehicle body member 300 is too large to be used as a resonance chamber, a capacity (volume) necessary for the resonance chamber 310 may be provided in the internal space of the vehicle body member 300.

Accordingly, to determine the capacity (volume) required only for the resonance chamber 310 in the internal space of the vehicle body member 300, partitions 312 and 314 are disposed at predetermined positions of both sides of the resonance chamber 310, respectively, and each of the partitions 312 and 314 is integrally welded to an internal surface of the vehicle body member 300.

Therefore, a space formed by upper, lower, right and left faces of the vehicle body member 300 and the partitions 312 and 314 is employed as the resonance chamber 310.

In the muffler housing 100 of the present invention, a first baffle 111 and a second baffle 112 are mounted to be spaced from each other with a predetermined distance in a longitudinal direction thereof.

Therefore, a space formed between one side wall of the muffler housing 100 and the first baffle 111 acts as a first expansion chamber 101, a space between the first baffle 111 and the second baffle 112 acts as a second expansion chamber 102, and a space between the other side wall of the muffler housing 100 and the second baffle 112 acts as a third expansion chamber 103.

At the instant time, each of all the first baffle 111 and the second baffle 112 has a plurality of perforations 113 formed therein.

Furthermore, an internal tube 120 passes through the first baffle 111 and the second baffle 112 in the muffler housing 100 and is disposed in the longitudinal direction of the muffler housing 100, and an inlet end portion of the internal tube 120 is connected to an exhaust pipe 130 and an outlet end portion of the internal tube 120 is disposed in the third expansion chamber 103 to be configured for discharging exhaust gas.

At the instant time, a plurality of perforations 122 for discharging exhaust gas are formed in a section, which is disposed in the third expansion chamber 103, of the entire length region of the internal tube 120.

In the muffler housing 100, furthermore, two external tubes 140 passes through the first baffle 111 and the second baffle 112 and are disposed in the longitudinal direction of the muffler housing, an inlet end portion of the external tube 140 is disposed in the first expansion chamber 101 to allow exhaust gas to be accommodated, and an outlet end portion of the external tube 140 is disposed to pass through the other wall of the muffler housing 100 and to be exposed to the outside.

For reference, as shown in FIG. 3, a separate muffler cap 142 is mounted on the outlet end portion of the external tube 140 for improving aesthetics for external appearance.

Furthermore, a connection tube 150 configured to allow the first expansion chamber 101 to be directly in communication with the third expansion chamber 103 is connected between the first baffle 111 and the second baffle 112.

According to an exemplary embodiment of the present invention, the third expansion chamber 103, which is the expansion chamber to which exhaust gas is lastly discharged, of three separated expansion chambers 101, 102, 103 in the muffler housing 100 is connected to the resonance chamber 310 via the connection pipe 200, so that the third expansion chamber and the resonance chamber becomes in communication with each other.

A bellows pipe 202 which may be moved vertically and horizontally is adopted as the connection tube 200 to absorb a displacement of behavior of the muffler housing 100 caused by vehicle traveling vibration.

At the instant time, an upper end portion and a lower end portion of the bellows pipe 202 are welded to the vehicle body member 300 and the muffler housing 100, respectively, so that the internal to the bellows pipe 202 is hermetically sealed to prevent exhaust gas from being leaked.

Hereinafter, operational flow of the Helmholtz muffler of the present invention having the above described configuration is referred to as below.

When exhaust gas is discharged from the exhaust pipe 130 to the internal tube 120, exhaust gas is discharged continuously through a process in which exhaust gas is discharged to the third expansion chamber 103 via the perforations 122 formed in the outlet end portion of the internal tube 120, a process in which exhaust gas is discharged from the third expansion chamber 130 to the second expansion chamber 102 via the perforations of the second baffle 112, a process in which exhaust gas is discharged from the second expansion chamber 102 to the first expansion chamber 101 via the perforations of the first baffle 111 and is simultaneously discharged from the third expansion chamber 103 to the first expansion chamber 111 via the connection tube 150, and a process in which exhaust gas passes through the external tube 140 from the first expansion chamber 111 and is then discharged to the outside.

As described above, while exhaust gas flowing into the internal tube 120 passes sequentially through the third expansion chamber 103, the second expansion chamber 102 and the first expansion chamber 101, exhaust discharge noise (exhaust noise excluding low frequency component in the entire RPM region of an engine) is reduced.

When exhaust gas flowing into the internal tube 120 is discharged to the third expansion chamber 103 through the perforations 122 formed in the outlet end portion of the internal tube 120, since the third expansion chamber 103 is in communication with the resonance chamber 310, which is formed in the vehicle body member 300, through the bellows pipe 202 which is the connection pipe 200, exhaust gas is also discharged to the resonance chamber 310 via the bellows pipe 202 and then trapped. In the resonance chamber 310, at the instant time, noise of the low-frequency component in exhaust gas noise, which is unpleasant to an ear of human, is reduced.

As described above, since the internal space of the muffler housing 100 is used only for the expansion chambers which divides the internal space into three sections and the hollow vehicle body member 300 is used as the resonance chamber 310 connected to the third expansion chamber 103, both the capacity (volume) of the resonance chamber and a capacity of the expansion chamber may be increased, so that it is possible to enhance an effect of reduction of noise within the entire RPM region caused by the expansion chamber, as well as an effect of reduction of noise within the low frequency region caused by the resonance chamber formed in the vehicle body member.

Furthermore, it is possible to reduce noise within the low frequency region in the resonance chamber 310 formed in the vehicle body member 300, however, when it is necessary to further lower a low frequency resonance frequency to be reduced, by moving positions of the partitions 312 and 314 welded to both sides of the resonance chamber 310 to the external side to increases the volume of the resonance chamber or by use of a bellows pipe having a smaller internal cross-sectional surface area than that of the bellows pipe 202, resonance frequency for reducing exhaust noise may be lowered, and thus an effect of reduction of noise within the low frequency region may be further improved.

Meanwhile, referring to FIG. 6, by forming the resonance chamber 310 in the vehicle body member 300 instead of the muffler housing, it is possible to reduce the volume (capacity) of the third expansion chamber 103 in the muffler housing 100, reducing a size of the muffler housing. Therefore, it is possible to secure a layout space for components of an exhaust system and to simultaneously reduce manufacturing cost of the muffler case.

Meanwhile, it is possible to connect the bellows pipe of the Helmholtz muffler for a vehicle according to an exemplary embodiment of the present invention to the resonance chamber 310 of the vehicle body member 300 in a thread-fastening manner.

Referring to FIG. 7, to connect the bellows pipe 202 to the muffler housing 100 and the resonance chamber 310 in the vehicle body member 300 in a communicable manner, the lower end portion of the bellows pipe 202 is welded to the muffler housing 100, and a male threaded portion 204 is formed on an upper end portion of the bellows pipe.

Furthermore, a second male threaded portion 316 is formed to protrude on a lower surface of an external surface of the resonance chamber 310 in the vehicle body member 300.

At the instant time, a stopper 205 for guiding a completion of a fastening nut 318 and preventing a lowering of the fastening nut 318 is further integrally formed at a lower end portion of an external circumferential region of the first male threaded portion 204.

In the present configuration, the first male threaded portion 204 and the second male threaded portion 316 are fastened to each other by the fastening nut 318, so that a connection of the bellows pipe 202 to the resonance chamber 310 in the vehicle body member 300 is achieved.

The fastening nut 318 is preferentially fastened to the second male threaded portion 316 formed on the lower surface of the resonance chamber 310 to position the fastening nut 318 at an uppermost region of the second male screw portion 316, and the first male threaded portion 204 of the bellows pipe 202 is subsequently brought into close contact with the second male threaded portion 316. As such, the fastening nut 318 is screw-rotated and moved toward the first male threaded portion 204 positioned below the second male threaded portion, so that the first male threaded portion 204 and the second male threaded portion 316 share the fastening nut 318 and become a fastened state.

At the instant time, the fastening nut 318 is coupled until it contacts the stopper 205 formed at a lower end portion of the first male threaded portion.

Therefore, the first male threaded portion 204 and the second male threaded portion 316 share the fastening nut 318 to be fastened to each other. As a result, a connection of the bellows pipe 202 to the resonance chamber 310 in the vehicle body member 300 is completed.

The above described present invention provides the following effects.

Firstly, by use of the internal space of the muffler housing of the muffler only as the expansion chambers diving the internal space into several sections, and using the hollow vehicle body member as the resonance chamber connected to one of the expansion chambers, the capacity (volume) of the resonance chamber and the capacity of the expansion chambers may be increased, so that it is possible to enhance an effect of reduction of noise within the entire RPM zone obtained by the expansion chambers as well as an effect of reduction of noise within the low frequency range obtained by the resonance chamber formed in the vehicle body member.

Secondly, since the muffler housing may be applied to a case having a reduced size, it is possible to secure a layout space for components of the exhaust system and reduce manufacturing cost of the muffler case.

For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner”, “outer”, “up”, “down”, “upper”, “lower”, “upwards”, “downwards”, “front”, “rear”, “back”, “inside”, “outside”, “inwardly”, “outwardly”, “internal”, “external”, “inner”, “outer”, “forwards”, and “backwards” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and their practical application, to enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. A Helmholtz muffler for a vehicle, the muffler comprising: a muffler housing having an internal space divided into a plurality of expansion chamber; a resonance chamber formed hermetically in a vehicle body member; and a connection pipe connected to at least one of the plurality of expansion chambers of the muffler housing and to the resonance chamber.
 2. The Helmholtz muffler for the vehicle of claim 1, wherein partitions by which a capacity of the resonance chamber is determined are disposed at a first side and a second side of the resonance chamber, respectively, and the partitions are integrally secured to the vehicle body member to form the resonance chamber.
 3. The Helmholtz muffler for the vehicle of claim 1, wherein the connection pipe is connected to and is in fluidic communication with an expansion chamber to which exhaust gas is lastly discharged from the muffler housing, among the plurality of expansion chambers.
 4. The Helmholtz muffler for the vehicle of claim 1, wherein the connection pipe is a bellows pipe which is configured to be movable according to movement of the muffler case.
 5. The Helmholtz muffler for the vehicle of claim 4, wherein an upper end portion and a lower end portion of the bellows pipe are secured to the resonance chamber in the vehicle body member and the muffler housing, respectively.
 6. The Helmholtz muffler for the vehicle of claim 1, further including: a first baffle and a second baffle mounted in the muffler housing in a longitudinal direction of the muffler housing and spaced from each other to form a space between a first side wall of the muffler housing and the first baffle as a first expansion chamber among the plurality of expansion chamber, to form a space between the first baffle and the second baffle as a second expansion chamber among the plurality of expansion chamber, and to form a space between a second side wall of the muffler housing and the second baffle as a third expansion chamber among the plurality of expansion chamber.
 7. The Helmholtz muffler for the vehicle of claim 6, further including: an internal tube passing through the first baffle and the second baffle and being disposed in the muffler housing; and an exhaust pipe disposed outside the muffler housing and connected to a first end portion of the internal tube, wherein a second end portion of the internal tube is disposed in the third expansion chamber.
 8. The Helmholtz muffler for the vehicle of claim 6, further including: at least one external tube passing through the first baffle and the second baffle and disposed in the muffler housing, wherein a first end portion of the at least one external tube is disposed in the first expansion chamber and a second end portion thereof is disposed to pass through the second side wall of the muffler housing and exposed outside the muffler housing.
 9. The Helmholtz muffler for the vehicle of claim 7, wherein a plurality of perforations is formed in the first end portion of the at least one external tube.
 10. The Helmholtz muffler for the vehicle of claim 8, further including: a muffler cap mounted on the second end portion of the at least one external tube.
 11. The Helmholtz muffler for the vehicle of claim 6, further including: a connection tube passing through the first baffle and the second baffle and fluidically-connecting the first expansion chamber and the third expansion chamber to be in fluidical communication with each other.
 12. The Helmholtz muffler for the vehicle of claim 7, wherein a plurality of perforations is formed in a section among an entire length region of the internal tube, and wherein the section of the internal tune is disposed in the third expansion chamber.
 13. The Helmholtz muffler for the vehicle of claim 6, wherein a plurality of perforations is formed on the first baffle and the second baffle.
 14. The Helmholtz muffler for the vehicle of claim 4, wherein the bellows pipe has a first male threaded portion formed on an upper end portion thereof, wherein the resonance chamber in the vehicle body member has a second male threaded portion formed on an external surface thereof, and wherein the first male threaded portion and the second threaded portion are fastened to each other by a fastening nut to connect the bellows pipe to the resonance chamber in the vehicle body member.
 15. The Helmholtz muffler for the vehicle of claim 14, wherein the first male threaded portion further includes a stopper integrally formed at a lower end portion of an external circumferential region of the first male threaded portion for guiding a completion of the fastening nut and preventing a lowering of the fastening nut. 